Quiz on Classification of Elements and Periodic Properties
Quiz on Classification of Elements and Periodic Properties
The periodic table may be defined as the table which classifies all the known elements in accordance with their properties in such a way that elements with similar properties are grouped together in the same vertical column and dissimilar elements are separated from one another.
Law of triads:– According to the law of triads, elements were placed in a group of 3 and they were called triads. These were placed in the increasing order of atomic masses
Newland’s law of octaves:– The elements were placed in increasing order of their atomic weights and it was noted that every eighth element had properties similar to the first element.
The relationship was just like every eighth note that resembles the first in octaves of music. Newlands’s Law of Octaves seemed to be true to elements only up to calcium.
Mendeleev’s periodic law:
“The properties of the elements are a periodic function of their atomic weights.” Mendeleev arranged elements in horizontal rows and vertical columns of a table in order of their increasing atomic weights in such a way that the elements with similar properties occupied the same vertical column or group. Mendeleev left gaps under silicon and aluminium and those were known as Eka aluminium and Eka silicon.
Later it was discovered that Eka aluminium had properties similar to gallium and Eka silicon had properties similar to germanium.
According to modern periodic law,
“The physical and chemical properties of the elements are periodic functions of their atomic numbers”.
The modern form of the periodic table was discovered by henry Mosley and hence it was also called henry Mosley’s periodic table.
The Periodic Law revealed important analogies among the 94 naturally occurring elements (neptunium and plutonium like actinium and protoactinium are also found in pitchblende – an ore of uranium).
The horizontal rows of the periodic table are called periods while the vertical columns are called groups or families.